1. Field of the Invention
The present invention relates to a construction machine.
2. Background Art
For example, JP 11-124879A describes an upper slewing body of a construction machine, the upper slewing body comprising two engines.
Further, there has heretofore been known an upper slewing body 520 which comprises a slewing frame 21 and two engines 33 installed to the slewing frame 21, as illustrated in FIG. 12A. There has also heretofore been known an upper slewing body 620 which comprises one side frame 31 and two engines 33 mounted on the side frame 31, as illustrated in FIG. 12B. For example, “DEMAG CC6800” and “DEMAG CC8800-1” (DEMAG: registered trademark) offered by Demag Cranes & Components GmbH are known as a construction machine having an upper slewing body with such a structure.
Meanwhile, in a large construction machine, assembling or disassembling (hereinafter referred to as “assembling/disassembling”) of the construction machine is frequently performed for the purpose of transportation of the construction machine or for other purpose. In assembling/disassembling of a construction machine, an assembling-assisting hydraulic actuator is used. The assembling-assisting hydraulic actuator is used for attaching/detaching of a coupling pin for mutually coupling two or more components of a construction machine, and/or jack-up of a car body. Further, an assembling-assisting hydraulic power unit is used to supply hydraulic oil to the assembling-assisting hydraulic actuator. In the following description, a purpose of use of a hydraulic power unit (including the above assembling-assisting hydraulic power unit) which is used for allowing a construction machine in an assembled state to perform an additional operation different from a primary operation thereof will hereinafter be referred to as “additional purpose”.
When an owner of a construction machine possess a hydraulic power unit for an “additional purpose”, in addition to the construction machine, purchase, transportation, storage, etc., of the hydraulic power unit for the “additional purpose”, are liable to impose a financial burden and/or labor on the owner. In this situation, it is conceivable to divert a hydraulic device for performing a primary operation of the construction machine to an “additional purpose”. However, it is impossible or difficult for a conventional technique to achieve such diversion, as described below.
In the technique described in the above patent document, two or more devices making up a hydraulic oil supply unit are installed, respectively, on separate frames. Specifically, in an upper slewing body described in FIGS. 3 and 4 of the patent document, a set of an engine (27) and a hydraulic pump (31) is installed on each of right and left cab bed frames (21B), and a set of a fuel tank (40) and a hydraulic oil tank (41) is installed on a main frame (21M). In the above description, each code in brackets corresponds to that described in the patent document. The engine, the hydraulic pump, the fuel tank and the hydraulic oil tank are connected to each other to form one unit, thereby functioning as one device (hydraulic power unit) for supplying hydraulic oil. However, in the case where the set of the engine and the hydraulic pump and the set of the fuel tank and the hydraulic oil tank are installed, respectively, on two separate frames, as in the patent document, when the frames are in a separated state, it is impossible to operate or use the engine, the hydraulic pump, the fuel tank and the hydraulic oil tank, as one device (hydraulic power unit) for supplying hydraulic oil.
In the techniques described in FIGS. 12A and 12B, all of the engines 33 (two engines 33) provided in the construction machine are installed to one frame. Thus, it is impossible to divert only one of the engines 33 to an “additional purpose”.
Moreover, when a plurality of components including all of the engines 33 provided in the construction machine are formed as one hydraulic power unit, the resulting hydraulic power unit becomes large in size. Consequently, when this hydraulic power unit is used for an “additional purpose”, a space occupied by the hydraulic power unit is increased. Further, the hydraulic power unit having a large size leads to an increase in size and mass of a package during transportation of the hydraulic power unit, which is liable to give rise to a need for a special trailer, for example.